1. Field of the Invention
The invention relates to a drive train system. The invention further relates to a method for optimizing the power supply for a cooling system for cooling at least one assembly of a drive train system.
2. Description of the Related Art
Drive train systems for stationary or mobile applications, in particular those intended for use in vehicles comprise at least one driving engine, which, in cases of mobile application, is constructed, as a rule, as an internal combustion engine. These systems require, as a rule, a cooling system for dissipating the heat that is produced during the combustion process. As a rule, the cooling system comprises a coolant circuit for carrying a cooling medium, a cooling device, which, as a rule, is constructed as a heat exchanger, and a delivering device for circulating the coolant in the coolant circuit, which, as a rule, is a coolant circulating pump. Further associated with the cooling device is a device, taking the form of a fan or a ventilator, for realizing an optimal heat transfer to the environment and the transport of ambient air. In the known constructions, this fan is driven by the driving engine, in particular by the internal combustion engine. The volume of air that can thereby be supplied to the cooling device is proportional in this case to the speed (rpm) of the engine. A major drawback of this system consists in the slow response time and the inadequate adjustment of the available cooling capacity to the actual need. If too large a volume of air is supplied—that is, at high speed (rpm) of the driving engine—an unnecessarily large amount of power is consequently consumed for driving the fan. If the volume of air is too small, the engine adjusts its power downward. Further known are solutions in which the fan can be switched off or in which it is possible to engage various transmission ratios for driving the fan. These systems are also characterized by a slow response time and inadequate adjustment of the cooling capacity that is supplied through the cooling system to the actual need, which is governed by the drive train assembly or at least by the driving engine.
Other systems are characterized by the use of means for influencing the fan power between the driving engine and the fan. Conceivable are mechanical coupling systems, which close as a function of the temperature of the cooling medium, this resulting in a direct proportionality between the coupling or the applied pressure and the temperature in the cooling system, which is to be regarded as a major drawback of such a system. Thus, the actuating device itself, in particular the manipulated variable, has to be precisely laid out with respect to the temperature that adjusts in the cooling circuit. Furthermore, this system responds to existing temperature values, so that, on the one hand, the full theoretically possible cooling capacity cannot always be supplied by the cooling system and, on the other hand, the adjustment of the cooling capacity occurs with a time delay on account of the inertial response of the system.